Adhesive composition

ABSTRACT

Provided are an adhesive composition and an organic electronic device (OED) including the same, and more particularly, an adhesive composition, which may form an encapsulation structure effectively blocking moisture or oxygen flowing into an OED from the outside, thereby ensuring the lifespan of the OED, and facilitates coating in the process of forming the encapsulation structure of the OED, thereby preventing the problem of flow of bubbles into the encapsulation structure or blocking of a coating nozzle and thus enhancing processability, and an OED including the same.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Stage Entry of International ApplicationNo. PCT/KR2016/003008, filed on Mar. 24, 2016, and claims the benefit ofand priority to Korean Application No. 10-2015-0040743, filed on Mar.24, 2015, all of which are hereby incorporated by reference in theirentirety for all purposes as if fully set forth herein.

BACKGROUND 1. Field of the Invention

The present application relates to an adhesive composition, an organicelectronic device (OED) including the same, and a method ofmanufacturing the OED.

2. Discussion of Related Art

An OED is a device including an organic material layer in which electriccharges are exchanged using holes and electrons, and the OED may be, forexample, a photovoltaic device, a rectifier, a transmitter, or anorganic light emitting diode (OLED).

Among the OEDs, an OLED has lower power consumption and a higherresponse speed, and is more advantageous in reducing the thickness of adisplay device or lighting than a conventional light source. Such anOLED also has excellent space utilization, and is expected to be appliedto various fields including all types of portable devices, monitors,notebook computers and TVs.

For commercialization and expanded use of the OLED, the most criticalproblem is durability. Organic materials and metal electrodes includedin the OLED are very easily oxidized by an external factor, for example,moisture. Therefore, a product including an OLED is very sensitive toenvironmental factors. For this reason, various methods have beensuggested to effectively prevent the permeation of oxygen or moistureinto an OED such as an OLED from the outside.

Patent Document 1 discloses an adhesive capsulation composition film andan organic electroluminescent diode, where the composition is apolyisobutylene (PIB)-based pressure-sensitive adhesive and does nothave high processability and has low reliability under ahigh-temperature and high-humidity condition.

PRIOR ART DOCUMENT Patent Document

(Patent Document 1) Korean Unexamined Patent Application Publication No.2008-0088606

SUMMARY OF THE INVENTION

The present application provides an adhesive composition, which can forman encapsulation structure effectively blocking moisture or oxygenflowing into an OED from the outside, thereby ensuring the lifespan ofthe OED, and facilitates coating in the process of forming theencapsulation structure of the OED, thereby preventing the problem offlow of bubbles into the encapsulation structure or blocking of acoating nozzle and thus enhancing processability, and an OED includingthe same.

The present application relates to an adhesive composition. The adhesivecomposition may be an encapsulation material applied to encapsulate orcapsulate the OED such as an OLED. In one exemplary embodiment, theadhesive composition of the present application may be applied toencapsulate or capsulate at least one of the side surfaces of an organicelectronic element. Therefore, after being applied in capsulation, theadhesive composition may be present at a peripheral portion of the OED.

The term “OED” used herein refers to a product or device having astructure including an organic material layer in which electric chargesare exchanged using holes and electrons between a pair of facingelectrodes, and examples of the OED may include, but the presentapplication is not limited to, a photovoltaic device, a rectifier, atransmitter, and an OLED. In an exemplary embodiment of the presentapplication, the OED may be an OLED.

An adhesive composition for encapsulating an organic electronic elementmay include an olefin-based resin having one or more reactive functionalgroups, a thixotropic index (TI) according to General Equation 1 may bein the range of 1.35 to 5. The present application provides anencapsulation material, which has an excellent moisture barrier propertyand facilitates the realization of a desired encapsulation structure bycontrolling the thixotropic index (TI) of the adhesive compositionincluding an olefin-based resin.T=V _(0.5) /V ₅  [General Equation 1]

In General Equation 1, V_(0.5) is a viscosity of the adhesivecomposition measured using a Brookfield viscometer with an RV-7 spindleat a temperature of 25° C. and a rotational speed of 0.5 rpm, and V₅ isa viscosity of the adhesive composition measured using a Brookfieldviscometer with an RV-7 spindle at a temperature of 25° C. and arotational speed of 5 rpm.

In one exemplary embodiment, the thixotropic index (TI) of the adhesivecomposition of the present application may be in the range of 1.35 to 5,1.36 to 4.5, 1.37 to 4, 1.38 to 3.5, or 1.39 to 3.3. As the thixotropicindex (TI) of the adhesive composition is controlled as described above,an encapsulation structure having an excellent moisture barrier propertymay be provided via an olefin-based resin and the problem of bubblesflowing into the encapsulation material in a process of encapsulating anorganic electronic element or blocking of a nozzle during coating of thecomposition may be prevented, and thus processability and productivitymay be enhanced.

In one exemplary embodiment, the adhesive composition may have aviscosity, measured with respect to torque using a Brookfield viscometerwith an RV-7 spindle at a temperature of 25° C. and a rotational speedof 0.5 rpm, in the range of 100,000 to 1,000,000 cPs. Specifically, inthe present application, the viscosity may be, unless particularlydefined otherwise, measured using DV−II+Pro as a Brookfield viscometerwith an RV-7 spindle under conditions of a temperature of 25° C. and arotational speed of 0.5 rpm, and the viscosity range may be 100,000 to1,000,000 cPs, 100,000 to 500,000 cPs, or 100,000 to 460,000 cPs. As theviscosity of the composition at room temperature is controlled to be100,000 cPs or more, the precipitation of a material present in thecomposition, for example, a moisture absorbent or an inorganic fillercan be prevented, and a desired shape of encapsulation structure can beformed and maintained by coating a desired position with thecomposition.

A physical property such as the thixotropy or viscosity described abovemay be adjusted by kinds of components constituting the adhesivecomposition, a content ratio between the components or degrees ofcrosslinking the components. As long as satisfying the physicalproperty, materials constituting the composition are not particularlylimited. The exemplary adhesive composition may include an olefin-basedresin including one or more reactive functional groups, a curable resinand a reactive diluent. As the adhesive composition includes the curableresin and the reactive diluent as well as the olefin-based resin thathas a low water vapor transmission rate (WVTR), the present applicationmay provide an encapsulation material, which exhibits an excellentmoisture barrier performance, excellent durability and reliability athigh temperature and high humidity, and facilitates the realization of adesired encapsulation structure.

Meanwhile, in the specification, the term “thixotropy” used herein mayrefer to a property of the composition in which there is no fluidity ina stationary state, but there is fluidity when oscillated. A method ofmeasuring the thixotropic index (TI) is not particularly limited, andthe thixotropic index (TI) may be measured using a known device formeasuring variable physical properties in the art, for example,DV−II+Pro as a Brookfield viscometer.

In one exemplary embodiment, the adhesive composition may furtherinclude an inorganic filler. The inorganic filler, other than a moistureabsorbent that will be described below, may be included to control thethixotropic index (TI) of the adhesive composition. As described above,the thixotropic index (TI) of the adhesive composition needs to becontrolled within a specific range. A method of controlling thethixotropic index (TI) within the above range is not particularlylimited, but may use an adequate amount of the inorganic filler. Aspecific type of the filler that can be used in the present applicationmay be, but is not particularly limited to, for example, one or amixture of two or more of silica, calcium carbonate, alumina and talc.

Also, to increase coupling efficiency between a filler and an organicbinder, the present application may use a product which is subjected tosurface treatment with an organic material as the filler, or furtherinclude a coupling agent.

The adhesive composition of the present application may include theinorganic filler at 0.1 to 20 parts by weight, 0.5 to 18 parts by weightor 1 to 15 parts by weight with respect to 100 parts by weight of theolefin-based resin. The present application may provide an encapsulationmaterial for facilitating the realization of a desired encapsulationstructure in the present application by adjusting the content of theinorganic filler within the above range.

Also, the inorganic filler may have a BET surface area in the range of35 to 500 m²/g, 40 to 400 m²/g, 50 to 300 m²/g or 60 to 200 m²/g. Thespecific surface area is measured using a BET method, specifically, byadding 1 g of a sample of the inorganic filler into a tube and thenmeasuring a specific surface area at −195° C. using ASAP2020(Micromeritics, US) without pretreatment. The same sample may besubjected to such measurement 3 times, thereby obtaining an averagevalue. The present application may provide an encapsulation material forfacilitating the realization of a desired encapsulation structure in thepresent application by adjusting the specific surface area of theinorganic filler within the above range.

As described above, the adhesive composition of the present applicationmay include an olefin-based resin including one or more reactivefunctional groups. The olefin-based resin may have a WVTR of 50 g/m²·dayor less.

The adhesive composition of the present application may include anolefin-based resin satisfying the above WVTR range, and when consideringthat it is applied to encapsulate or capsulate an OED, it can provide anexcellent moisture barrier property. The “resin having a WVTR of 50g/m²·day or less” used herein may refer to a resin having a WVTR of 50g/m²·day or less, measured in a thickness direction of a film when thefilm is formed in a layer of the resin to a thickness of 100 μm. TheWVTR may be 50, 40, 30, 20 or 10 g/m²·day or less, measured at 100° F.and a relative humidity of 100%. As the WVTR is lower, a more excellentmoisture barrier property may be exhibited. The lower limit may be, butis not particularly limited to, for example, 0 g/m²·day or 0.1 g/m²·day.

In detail, the exemplary olefin-based resin of the present applicationincludes an olefin-based resin derived from a mixture of monomers, andthe mixture may have an isoolefin monomer component or multiolefinmonomer component having at least 4 to 7 carbon atoms. The isoolefin maybe present in the range of, for example, 70 to 100 wt % or 85 to 99.5 wt% with respect to the total weight of the monomer. Themultiolefin-derived component may be present in the range of 0.5 to 30wt %, 0.5 to 15 wt % or 0.5 to 8 wt %.

The isoolefin may be, for example, isobutylene, 2-methyl-1-butene,3-methyl-1-butene, 2-methyl-2-butene, 1-butene, 2-butene, methyl vinylether, indene, vinyltrimethylsilane, hexene or 4-methyl-1-pentene. Themultiolefin may have 4 to 14 carbon atoms, and may be, for example,isoprene, butadiene, 2,3-dimethyl-1,3-butadiene, myrcene,6,6-dimethyl-fulvene, hexadiene, cyclopentadiene or piperylene. Otherpolymerizable monomers, for example, styrene and dichlorostyrene mayalso be homopolymerized or copolymerized.

In the present application, the olefin-based resin may include anisobutylene-based homopolymer or copolymer. As described above, anisobutylene-based olefin-based resin or polymer may refer to anolefin-based resin or polymer including 70 mol % or more ofisobutylene-derived repeat units and one or more different polymerizableunits.

In the present application, the olefin-based resin may be butyl rubberor branched butyl-like rubber. The exemplary olefin-based resin is aunsaturated butyl rubber such as a copolymer of an olefin or isoolefinand a multiolefin. As the olefin-based resin included in the adhesivecomposition of the present application, poly(isobutylene-co-isoprene),polyisoprene, polybutadiene, polyisobutylene,poly(styrene-co-butadiene), natural rubber, butyl rubber and a mixturethereof may be used. The available olefin-based resin in the presentapplication may be prepared by any of the suitable means known in theart, and the present application is not limited to the method ofpreparing the olefin-based resin.

In one exemplary embodiment, the olefin-based resin may be a lowmolecular weight polyisobutylene resin. For example, the olefin-basedresin may have a weight average molecular weight of 100,000 or less, and500 or more or 55,000 or more. The present application may realize asuitable adhesive composition for coating and capsulating processes bycontrolling the weight average molecular weight of the olefin-basedresin in the above range. The adhesive composition may have a liquidphase, and may be suitably applied to encapsulate side surfaces of thefollowing OED.

The reactive functional group included in the olefin-based resin may bea polar functional group. Also, the reactive functional group may havereactivity with the above-described curable resin. A type of thereactive functional group is not particularly limited, and may be, forexample, an acid anhydride group, a carboxyl group, an epoxy group, anamino group, a hydroxyl group, an isocyanate group, an oxazoline group,an oxetane group, a cyanate group, a phenol group, a hydrazide group oran amide group. Examples of the olefin-based resin having the reactivefunctional group may include succinic anhydride-modifiedpolyisobutylene, maleic anhydride-modified liquid polyisobutylene,maleic anhydride-modified liquid polyisoprene, epoxy-modifiedpolyisoprene, hydroxyl group-modified liquid polyisoprene, andallyl-modified liquid polyisoprene. The present application may realizean adhesive composition having physical properties such as desiredmoisture barrier property and handleability in the present applicationby forming a crosslinked structure between the above-describedolefin-based resin and a curable resin which will be described below.

In an exemplary embodiment of the present application, the adhesivecomposition may include a curable resin capable of reacting with theolefin-based resin. The curable resin may be a heat-curable resin or aphotocurable resin. The curable resin may be a resin including at leastone curable functional group. A specific type of the curable resin thatcan be used in the present application is not particularly limited, andmay be, for example, various curable resins known in the art.

In the specification, the term “heat-curable resin” refers to a resinthat can be cured by suitable heating or an aging process, and the term“photocurable resin” used herein refers to a resin that can be cured byirradiation of electromagnetic waves. For example, the photocurableresin may be a photocationic curable resin or a photoradical curableresin.

In the present application, a specific type of the curable resin is notparticularly limited as long as a resin has the above-describedproperties. For example, the curable resin may have an adhesive propertyafter being cured, and may be a resin including one or more heat-curablefunctional groups such as an epoxy group, a glycidyl group, anisocyanate group, a hydroxyl group, a carboxyl group or an amide group,or a resin including one or more functional groups that can be cured byirradiation of electromagnetic waves, for example, a urethane group, anepoxide group, a cyclic ether group, a sulfide group, an acetal group ora lactone group. Also, a specific type of the above-described resin maybe, but is not limited to, an acrylic resin, a polyester resin, anisocyanate resin or an epoxy resin, and preferably, an epoxy acrylate ora urethane acrylate.

In an exemplary embodiment of the present application, as the curableresin, an aromatic or aliphatic, or linear or branched epoxy resin maybe used. In one exemplary embodiment of the present application, anepoxy resin may contain at least two or more functional groups and havean epoxy equivalent weight of 180 to 1,000 g/eq. Characteristics of acured product such as adhesive performance and a glass transitiontemperature may be effectively maintained by the epoxy resin having theabove range of the epoxy equivalent weight. Such an epoxy resin may beone or a mixture of two or more of a cresol novolac epoxy resin, abisphenol A-type epoxy resin, a bisphenol A-type novolac epoxy resin, aphenol novolac epoxy resin, a tetrafunctional epoxy resin, abiphenyl-type epoxy resin, a triphenol methane-type epoxy resin, analkyl-modified triphenol methane epoxy resin, a naphthalene-type epoxyresin, a dicyclopentadiene-type epoxy resin, and adicyclopentadiene-modified phenol-type epoxy resin.

In the present application, as a heat-curable resin, an epoxy resinhaving a cyclic structure in a molecular structure may be used, and forexample, an alicyclic epoxy resin may be used. Since the alicyclic epoxyresin has excellent compatibility with an olefin-based resin or areactive diluent, it is cured without phase separation, and therefore,uniform crosslinks in an adhesive may be realized.

In one exemplary embodiment, the curable resin may be included at 10 to70 parts by weight with respect to 100 parts by weight of theolefin-based resin. Specifically, the curable resin may be included at10 to 70 parts by weight, 15 to 65 parts by weight or 20 to 60 parts byweight with respect to 100 parts by weight of the olefin-based resin.The present application may provide an adhesive composition, which canensure thermal resistance after being cured and simultaneously exhibitan excellent moisture barrier property or durability and reliability, bycontrolling the content of the curable resin in the above range.

Also, in an exemplary embodiment of the present application, theadhesive composition may include a curing agent. The curing agent may bea heat-curing agent or photocuring agent. For example, a suitable typeof curing agent may be selected and used depending on the type of thecurable resin or a functional group included in the curable resin, andone or more types of curing agents may be used.

In one exemplary embodiment, when the curable resin is an epoxy resin,as a curing agent for an epoxy resin known in the art, for example, oneor two or more of an amine curing agent, an imidazole curing agent, aphenol curing agent, a phosphorus curing agent and an acid anhydridecuring agent may be used, but the present application is not limitedthereto.

In one exemplary embodiment, as the curing agent, an imidazole compound,which is in a solid phase at room temperature and has a melting point ordecomposition temperature of 80° C. or more, may be used. Such acompound may be, for example, 2-methyl imidazole, 2-heptadecylimidazole, 2-phenyl imidazole, 2-phenyl-4-methyl imidazole or1-cyanoethyl-2-phenyl imidazole, but the present application is notlimited thereto.

In an exemplary embodiment of the present application, the curing agentmay be a latent heat-curing agent such as an imidazole-isocyanuric acidaddition product, an amine-epoxy addition product, a borontrifluoride-amine complex or a capsulated imidazole. That is, in thepresent application, light irradiation may be first performed in acuring process for the adhesive composition to control initial fluidity,and the curing agent, as a latent curing agent, may serve to cure acurable resin in main curing after the light irradiation.

A content of the curing agent may be selected depending on a compositionof the composition, for example, a type or ratio of the curable resin.For example, the curing agent may be included at 1 to 100 parts byweight, 1 to 90 parts by weight or 1 to 80 parts by weight with respectto 100 parts by weight of the curable resin. The weight ratio may beadjusted according to the type and ratio of the curable resin or afunctional group thereof, or a crosslinking density to be realized.

When the curable resin is a resin that can be cured by the irradiationof an active energy ray, as an initiator, for example, a cationicphotopolymerization initiator or a photoradical initiator may be used.

As the cationic photopolymerization initiator, an onium salt- ororganometallic salt-based ionized cationic initiator, or an organicsilane- or latent sulfonic acid-based non-ionized cationicphotopolymerization initiator may be used. The onium salt-basedinitiator may be a diaryliodonium salt, a triarylsulfonium salt or anaryldiazonium salt, the organometallic salt-based initiator may be ironarene, the organic silane-based initiator may be o-nitrobenzyl triarylsilyl ether, triaryl silyl peroxide or acyl silane, and the latentsulfonic acid-based initiator may be α-sulfonyloxy ketone orα-hydroxymethylbenzoin sulfonate, but the present application is notlimited thereto.

In an exemplary embodiment of the present application, the adhesivecomposition may include a reactive diluent. Also, the reactive diluentmay include a photocurable compound, specifically, a radicalphotocurable compound. In the specification, a type of the radicalphotocurable compound may be different from the above-described curableresin. As the adhesive composition includes the reactive diluent, thepresent application may provide an encapsulation material which cansatisfy a physical property such as desired thixotropy and thusfacilitates the realization of a desired encapsulation structure. Also,since the reactive diluent is included, the adhesive composition of thepresent application may have a solventless-type liquid phase.

Also, to seal the side surfaces of the organic electronic element, aprocess of coating the surfaces with a liquid adhesive composition isperformed. However, conventionally, after coating, there is difficultyin maintaining a desired capsulated shape due to the high fluidity ofthe composition. In the present application, the adhesive compositionthat has been applied to a desired position may be precured by lightirradiation to control fluidity, and then subjected to main curing.Therefore, in the present application, the applied adhesive compositionmay be maintained in the desired capsulated shape before main curing.That is, in the present application, as the adhesive compositionincludes both of the curable resin and the radical photocurablecompound, a double curing method may be introduced, and therefore thefluidity of the adhesive composition can be controlled at hightemperature after coating.

The radical photocurable compound may include, for example, amultifunctional polymerizable compound which has high compatibility withthe above-described olefin-based resin and curable resin and is capableof forming a specific crosslinked structure. Also, in one exemplaryembodiment, the crosslinked structure may be a crosslinked structureformed by heating, a crosslinked structure formed by the irradiation ofactive energy rays or a crosslinked structure formed by aging at roomtemperature. Here, in the category of the “active energy rays”,microwaves, infrared (IR) rays, UV (UV) rays, X rays, gamma rays, andparticle beams including alpha-particle beams, proton beams, neutronbeams and electron beams may be included, and generally, UV rays orelectron beams may be used.

In an exemplary embodiment, the radical photocurable compound may be amultifunctional active energy ray-polymerizable compound, which may be,for example, a compound including two or more functional groups capableof participating in polymerization by the irradiation of active energyrays, for example, functional groups including an ethylene-likeunsaturated double bond such as acryloyl groups, methacryloyl groups,acryloyloxy groups or methacryloyloxy groups or functional groups suchas epoxy groups or oxetane groups. In one exemplary embodiment, themultifunctional active energy ray-polymerizable compound may be a bi- orhigher functional compound.

In an exemplary embodiment of the present application, as themultifunctional active energy ray-polymerizable compound, for example, amultifunctional acrylate (MFA) may be used.

In an exemplary embodiment of the present application, the radicalphotocurable compound may satisfy Formula 1.

In Formula 1, R₁ is hydrogen or an alkyl group having 1 to 4 carbonatoms, n is an integer of 2 or higher, and X is a residue derived from alinear, branched or cyclic alkyl or alkenyl group having 3 to 30 carbonatoms. Here, when X is a residue derived from a cyclic alkyl or alkenylgroup, X may be a residue derived from a cyclic alkyl or alkenyl grouphaving 3 to 30, 4 to 28, 6 to 28, 8 to 22, or 12 to 20 carbon atoms.Also, when X is a residue derived from a linear alkyl or alkenyl group,X may be a residue derived from a linear alkyl or alkenyl group having 3to 30, 4 to 28, 6 to 25, or 8 to 20 carbon atoms. Also, when X is aresidue derived from a branched alkyl or alkenyl group, X may be aresidue derived from a branched alkyl or alkenyl group having 3 to 30, 4to 28, 5 to 25, or 6 to 20 carbon atoms.

The term “residue derived from an alkyl or alkenyl group” used hereinmay refer to a residue of a specific compound, for example, an alkyl oralkenyl group. In an exemplary embodiment, in Formula 1, when n is 2, Xmay be an alkylene or alkylidene group. Also, when n is 3 or higher, Xmay be an alkyl or alkenyl group from which two or more hydrogen atomsare released and then linked to a (meth)acryloyl group of Formula 1. nmay be one in the range of 2 to 20.

The term “alkyl group” or “alkenyl group” used herein may be, unlessparticularly defined otherwise, an alkyl or alkenyl group having 1 to30, 1 to 25, 1 to 20, 1 to 16, 1 to 12, 1 to 8, or 1 to 4 carbon atoms.The alkyl or alkenyl group may have a linear, branched or cyclicstructure, and may be arbitrarily substituted by one or moresubstituents.

The term “alkylene group” or “alkylidene group” used herein may be,unless particularly defined otherwise, an alkylene or alkylidene grouphaving 2 to 30, 2 to 25, 2 to 20, 2 to 16, 2 to 12, 2 to 10, or 2 to 8carbon atoms. The alkylene or alkylidene group may have a linear,branched or cyclic structure, and may be arbitrarily substituted by oneor more substituents.

The term “alkoxy group” used herein may be, unless particularly definedotherwise, an alkoxy group having 1 to 20, 1 to 16, 1 to 12, 1 to 8, or1 to 4 carbon atoms. The alkoxy group may have a linear, branched orcyclic structure. Also, the alkoxy group may be arbitrarily substitutedby one or more substituents.

In one exemplary embodiment, the multifunctional active energyray-polymerizable compound that can be polymerized by the irradiation ofactive energy rays may be polybutadiene dimethacrylate, 1,4-butanedioldi(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,12-dodecanedioldi(meth)acrylate, neopentyl glycol di(meth)acrylate, dicyclopentanyldi(meth)acrylate, cyclohexane-1,4-dimethanol di(meth)acrylate,tricyclodecane dimethanol (meth)diacrylate, dimethylol dicyclopentanedi(meth)acrylate, neopentyl glycol-modified trimethylolpropanedi(meth)acrylate, adamantane di(meth)acrylate, trimethylolpropanetri(meth)acrylate, or mixtures thereof.

The reactive diluent may be included at 10 to 100 parts by weight, 10 to90 parts by weight, 13 to 80 parts by weight, 14 to 70 parts by weightor 14 to 65 parts by weight with respect to 100 parts by weight of theolefin-based resin. The present application may realize a suitableviscosity for the application of the composition by controlling thecontent of the reactive diluent to 100 parts by weight or less, and mayrealize a desired thixotropic index (TI) in the present application bycontrolling the content of the reactive diluent to 10 parts by weight ormore. Also, the present application may provide a cured product of anadhesive which can maintain a capsulated structure when precured byadjusting the content of the reactive diluent in the above range.

In an exemplary embodiment, the adhesive composition may include aradical initiator as well as the reactive diluent. The radical initiatormay be a photoradical initiator. A specific type of the photoinitiatormay be suitably selected by considering a curing rate and yellowingprobability. For example, a benzoin-based, hydroxy ketone-based, aminoketone-based or phosphine oxide-based photoinitiator may be used, andspecifically, benzoin, benzoin methylether, benzoin ethylether, benzoinisopropylether, benzoin n-butylether, benzoin isobutylether,acetophenone, dimethylamino acetophenone,2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone,2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexyl phenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one,4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone,p-phenyl benzophenone, 4,4′-diethylaminobenzophenone,dichlorobenzophenone, 2-methylanthraquinone, 2-ethyl anthraquinone,2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone,2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone,2,4-diethylthioxanthone, benzyldimethylketal, acetophenonedimethylketal, p-dimethylamino benzoic acid ester,oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] or2,4,6-trimethylbenzoyl-diphenyl-phosphineoxide may be used.

A content of the photoradical initiator may be changed by the type andratio of a functional group of the radical photocurable compound, or acrosslinking density to be realized. For example, the photoradicalinitiator may be mixed at 0.1 to 80 parts by weight or 0.1 to 60 partsby weight with respect to 100 parts by weight of the reactive diluent.The present application may introduce a suitable crosslinked structureto the adhesive composition by controlling the content of thephotoradical initiator in the above range, and therefore the fluiditymay be controlled at high temperature.

In one exemplary embodiment, the adhesive composition of the presentapplication may include 40 to 90 parts by weight of the olefin-basedresin having one or more reactive functional groups, 5 to 50 parts byweight of the curable resin, and 1 to 40 parts by weight of the reactivediluent. In another exemplary embodiment, the adhesive composition mayinclude 50 to 80 parts by weight of the olefin-based resin, 10 to 40parts by weight of the curable resin, and 5 to 30 parts by weight of thereactive diluent. The present application may provide an encapsulationmaterial, which exhibits an excellent moisture barrier performance, hasexcellent durability and reliability at both of high temperature andhigh humidity, and facilitates the realization of a desiredencapsulation structure by adjusting the content of each component ofthe adhesive composition in the above range.

The adhesive composition of the present application may also include amoisture absorbent. The term “moisture absorbent” used herein may be ageneral term for a component capable of adsorbing or removing moistureor vapor introduced from the outside through a physical or chemicalreaction. That is, the moisture absorbent may refer to a moisturereactive absorbent, a physical absorbent, or a mixture thereof.

The moisture reactive absorbent chemically reacts with vapor, moistureor oxygen flowing into the resin composition or cured product thereof toadsorb the moisture or vapor. The physical absorbent allows to prolong amigration pathway of the moisture or vapor permeating the resincomposition or cured product thereof, and thus may inhibit thepermeation of the moisture or vapor and maximize a barrier propertyagainst the moisture and vapor through a matrix structure of the resincomposition or cured product thereof and an interaction with themoisture reactive absorbent.

A specific type of the moisture absorbent that can be used in thepresent application may be, but is not particularly limited to, forexample, one or a mixture of two or more of a metal oxide, a metal salt,and phosphorus pentoxide (P₂O₅) as a moisture reactive absorbent, andmay be zeolite, zirconia or montmorillonite as a physical absorbent.

Here, specifically, the metal oxide may be lithium oxide (Li₂O), sodiumoxide (Na₂O), barium oxide (BaO), calcium oxide (CaO) or magnesium oxide(MgO), and the metal salt may be, but is not limited to, a sulfate suchas lithium sulfate (Li₂SO₄), sodium sulfate (Na₂SO₄), calcium sulfate(CaSO₄), magnesium sulfate (MgSO₄), cobalt sulfate (CoSO₄), galliumsulfate (Ga₂(SO₄)₃), titanium sulfate (Ti(SO₄)₂), or nickel sulfate(NiSO₄); a metal halide such as calcium chloride (CaCl₂), magnesiumchloride (MgCl₂), strontium chloride (SrCl₂), yttrium chloride (YCl₃),copper chloride (CuCl₂), cesium fluoride (CsF), tantalum fluoride(TaF₅), niobium fluoride (NbF₅), lithium bromide (LiBr), calcium bromide(CaBr₂), cesium bromide (CeBr₃), selenium bromide (SeBr₄), vanadiumbromide (VBr₃), magnesium bromide (MgBr₂), barium iodide (BaI₂), ormagnesium iodide (MgI₂); or a metal chlorate such as barium perchlorate(Ba(ClO₄)₂) or magnesium perchlorate (Mg(ClO₄)₂).

In the present application, the moisture absorbent such as the metaloxide, which has been suitably processed, may be mixed with thecomposition. For example, a grinding process for the moisture absorbentmay be needed, and to this end, three-roll milling, bead milling or ballmilling may be used.

The adhesive composition of the present application may include themoisture absorbent at 5 to 100 parts by weight, 5 to 90 parts by weight,5 to 80 parts by weight or 10 to 50 parts by weight with respect to 100parts by weight of the olefin-based resin. In the adhesive compositionof the present application, the content of the moisture absorbent may becontrolled to be 5 parts by weight or more, so that the adhesivecomposition or cured product thereof may exhibit the excellent moistureand vapor barrier property. Also, as the content of the moistureabsorbent is controlled to be 100 parts by weight or less, when a thinfilm-type encapsulation structure is formed, an excellent moisturebarrier property may be exhibited.

In one exemplary embodiment, the adhesive composition may be a liquid atroom temperature, for example, about 25° C. In an exemplary embodimentof the present application, the adhesive composition may be asolventless-type liquid. The adhesive composition may be applied toencapsulate an organic electronic element, and specifically, toencapsulate the side surfaces of the organic electronic element. In thepresent application, since the adhesive composition is a liquid at roomtemperature, the element may be encapsulated by a method of coating theside surfaces of the organic electronic element with the composition.

In the adhesive composition of the present application, in addition tothe above-described components, various additives may be includedwithout affecting the above-described effects of the presentapplication. For example, the resin composition may include a defoamingagent, a coupling agent, a tackifier, a UV stabilizer or an antioxidantat a proper range of content according to desired physical properties.In one exemplary embodiment, the adhesive composition may furtherinclude a defoaming agent. As the present application includes adefoaming agent, a defoaming property is realized in the above-describedcoating process of the adhesive composition, and thus a reliableencapsulation structure may be provided. Also, as long as the physicalproperties of the adhesive composition required in the presentapplication are satisfied, the type of a defoaming agent is notparticularly limited.

The exemplary adhesive composition may have a viscosity of 700 to 5,000Pa·s after light irradiation. Within the above range of viscosity, theadhesive composition may maintain a desired shape of the encapsulationstructure. In one exemplary embodiment, the viscosity of the adhesivecomposition may be measured after the adhesive composition is irradiatedwith light in the UV-A wavelength range at a dose of 3 J/cm². Also, theviscosity of the adhesive composition may be the viscosity measured withrespect to shear stress under conditions of a temperature of 25° C., astrain of 10% and a frequency of 1 Hz. In one exemplary embodiment, theviscosity of the composition may be 700 to 4,000 Pa·s, 800 to 3,000 Pa·sor 900 to 2,000 Pa·s.

The term “UV-A wavelength range” used herein may refer to the wavelengthrange of 315 to 400 nm. Specifically, in the specification, the lighthaving the UV-A wavelength range may refer to light having any onewavelength in the range of 315 to 400 nm, or light having two or morewavelengths in the range of 315 to 400 nm.

In an exemplary embodiment of the present application, the adhesivecomposition may form an encapsulation structure of an OED by main curingafter the light irradiation. The main curing may be performed by theheating or light irradiation. To form the encapsulation structure, theadhesive composition needs physical properties such that main curing canbe performed without a change in a shape of the UV-precured compositioneven at the high curing temperature. That is, it is necessary to preventthe phenomenon of diffusing the adhesive composition at hightemperature. In one exemplary embodiment, the adhesive composition maybe precured by irradiation of light in the UV-A wavelength range at adose of 3 J/cm² as described above, and the precured resin compositionmay have a viscosity of 500 to 2,000 Pa·s, which is measured withrespect to shear stress under conditions of a temperature of 80° C., astrain of 10% and a frequency of 1 Hz. The viscosity may be, forexample, 500 to 1,800 Pa·s, 500 to 1,600 Pa·s or 600 to 1,500 Pa·s. Theadhesive composition of the present application may satisfy the aboverange of viscosity, and therefore may be effectively applied toencapsulate the side surfaces of an OED.

The present application also relates to an OED. The exemplary OED mayinclude, as shown in the FIGURE, a substrate 21; an organic electronicelement 23 formed on the substrate 21; and a side encapsulation layer 10formed on a peripheral portion of the substrate 21 to surround sidesurfaces of the organic electronic element 23, and including theabove-described adhesive composition. Also, the exemplary OED mayfurther include a entire encapsulation layer 11 covering the entiresurface of the organic electronic element 23.

The entire encapsulation layer and the side encapsulation layer may beformed in the same plane. Here, the term “same” used herein may meansubstantially the same. For example, the expression “substantially thesame” in the same plane” means that there may be an error of ±5 or ±1 μmin a thickness direction. The entire encapsulation layer may encapsulatethe top surface of the element, or encapsulate the side surfaces of theelement as well as the top surface thereof. The side encapsulation layermay be formed on the side surfaces of the element, but may not be indirect contact with the side surfaces of the organic electronic element.For example, the organic electronic element may be encapsulated suchthat the entire encapsulation layer may be in direct contact with thetop and side surfaces of the element. That is, the side encapsulationlayer may not be in contact with the element, but may be disposed on theperipheral portion of the substrate in the plan view of the OED.

The term “peripheral portion” used herein refers to an edge. That is, aperipheral portion of the substrate may mean an edge of the substrate.

A material for constituting the side encapsulation layer may include,but is not particularly limited to, the above-described adhesivecomposition.

Meanwhile, the entire encapsulation layer may include an encapsulationresin, and the encapsulation resin may be an acrylic resin, an epoxyresin, a silicone resin, a fluorine resin, a styrene resin, a polyolefinresin, a thermoplastic elastomer, a polyoxyalkylene resin, a polyesterresin, a polyvinyl chloride resin, a polycarbonate resin, apolyphenylenesulfide resin, a polyamide resin or a mixture thereof. Acomponent for constituting the entire encapsulation layer may be thesame as or different from the above-described adhesive composition.However, since the entire encapsulation layer is in direct contact withthe element, the entire encapsulation layer may not include or mayinclude a small amount of the above-described moisture absorbent. Forexample, the entire encapsulation layer may be included at 0 to 20 partsby weight with respect to 100 parts by weight of the encapsulationresin.

In one exemplary embodiment, the organic electronic element may includea reflective electrode layer formed on a substrate, an organic layerformed on the reflective electrode layer and at least including anemitting layer, and a transparent electrode layer formed on the organiclayer.

In the present application, the organic electronic element 23 may be anOLED.

In one exemplary embodiment, the OED according to the presentapplication may be, but is not limited to, a top-emission OED or abottom-emission OED.

The OED may further include a protective film for protecting the organicelectronic element between the above-described entire encapsulationlayer or side encapsulation layer and the organic electronic element.

Also, the present application relates to a method of manufacturing anOED.

In one exemplary embodiment, the manufacturing method may includeapplying the above-described adhesive composition to a peripheralportion of a substrate 21 on which an organic electronic element 23 isformed to surround side surfaces of the organic electronic element 23.The application of the adhesive composition may be a step for formingthe above-described side encapsulation layer 10.

In detail, the formation of the side encapsulation layer may includeapplying the above-described adhesive composition to the organicelectronic element 23 to surround the side surfaces of the organicelectronic element 23, and further include performing precuring and maincuring on the adhesive composition. The precuring may include lightirradiation, and the main curing may include light irradiation orheating.

Here, the substrate 21 on which the organic electronic element 23 isformed may be manufactured by forming a reflective electrode or atransparent electrode on the substrate 21 such as a glass or film byvacuum deposition or sputtering, and forming an organic material layeron the reflective electrode. The organic material layer may include ahole injection layer, a hole transport layer, an emitting layer, anelectron injection layer and/or an electron transport layer.Subsequently, a second electrode may be further formed on the organicmaterial layer. The second electrode may be a transparent electrode or areflective electrode. Afterward, the above-described side encapsulationlayer 10 is applied to the peripheral portion of the substrate 21 tocover the side surfaces of the organic electronic element 23. Here, amethod of forming the side encapsulation layer 10 is not particularlylimited, and may use a technique such as screen printing or dispensercoating to coat the side surfaces of the substrate 21 with theabove-described adhesive composition. Also, a entire encapsulation layer11 for encapsulating the entire surface of the organic electronicelement 23 may be applied. A method of forming the entire encapsulationlayer 11 may use a technique known in the art, for example, one dropfilling.

Also, in the present application, a curing process may be performed onthe full or side encapsulation layer for encapsulating an OED, and sucha curing process (main curing) may be performed in, for example, aheating chamber or a UV chamber, and preferably performed in bothchambers. Conditions for the main curing may be suitably selectedaccording to the stability of an OED.

In one exemplary embodiment, after the coating of the above-describedadhesive composition, the composition may be irradiated with light toinduce crosslinking. The light irradiation may include irradiating thecomposition with light in the UV-A wavelength range at a dose of 0.3 to6 J/cm² or 0.5 to 4 J/cm². As described above, a basic shape of theencapsulation structure may be realized by precuring through lightirradiation.

In one exemplary embodiment, the manufacturing method may includeperforming main curing on the adhesive composition precured by the lightirradiation. The main curing may further include heat curing at atemperature of 40 to 100° C. for 1 to 24 hours, 1 to 20 hours, 1 to 10hours or 1 to 5 hours. Also, the main curing may include irradiation oflight in the UV-A wavelength range at a dose of 0.3 to 6 J/cm² or 0.5 to4 J/cm². The adhesive composition may be subjected to the main curing byheating or light irradiation.

Effect

The present application provides an adhesive composition which can forman encapsulation structure for effectively blocking moisture or oxygenflowing into an OED from the outside, thereby ensuring the lifespan ofthe OED, and can prevent flow of bubbles into the encapsulationstructure or blocking of a coating nozzle due to coatability in theprocess of forming the encapsulation structure of the OED, therebyenhancing processability, and an OED including the same.

BRIEF DESCRIPTION OF THE DRAWINGS

The FIGURE is a cross-sectional view of an OED according to an exemplaryembodiment of the present application.

EXPLANATION OF REFERENCE NUMERALS

1: adhesive

10: side encapsulation layer

11: entire encapsulation layer

21: substrate

22: cover substrate

23: organic electronic element

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, the present application will be described in further detailwith reference to examples according to the present application andcomparative examples not according to the present application, and thescope of the present application is not limited to the followingexamples.

Example 1

As main components, an olefin-based resin, that is, an acidanhydride-modified polyisobutylene resin (BASF, Mn 1000 g/mol, GlissopalSA), curable resins, that is, an alicyclic epoxy resin (Tohto Kasei,ST-3000, epoxy equivalent weight: 230 g/eq, viscosity: 3000 cPs) and anepoxy acrylate (Sartomer, CN110), and reactive diluents, that is, apolybutadiene dimethacrylate (Sartomer, CN301) and 1,6-hexanedioldiacrylate (HDDA) were put into a mixing vessel in a weight ratio of70:10:10:6:4 (GlissopalSA:ST-3000:CN110:CN301:HDDA) at room temperature.As a radical initiator, 5 parts by weight of2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651, Ciba) was put intothe vessel with respect to 100 parts by weight of the main components,and as a heat-curing agent, 10 parts by weight of an imidazole-basedcuring agent (Shikoku, 2P4MZ) was put into the vessel with respect to100 parts by weight of the main components. Also, 1 part by weight offumed silica (Aerosil, Evonik, R805, particle size: 10˜20 nm, BET=150m²/g) as an inorganic filler was put into the vessel with respect to 100parts by weight of the main components. Meanwhile, 10 parts by weight ofcalcium oxide (CaO, Aldrich) as a moisture absorbent was further putinto the vessel with respect to 100 parts by weight of the maincomponents.

A homogeneous composition solution was prepared by agitating the mixingvessel using a planetary mixing device (Kurabo Industries, KK-250s).

Example 2

As main components, an olefin-based resin, that is, an acidanhydride-modified polyisobutylene resin (BASF, Mn 1000 g/mol, GlissopalSA), curable resins, that is, an alicyclic epoxy resin (Daicel,Celloxide 2021P, epoxy equivalent weight: 130 g/eq, viscosity: 250 cPs)and an epoxy acrylate (Sartomer, CN110), and reactive diluents, that is,a polybutadiene dimethacrylate (Sartomer, CN301) and 1,6-hexanedioldiacrylate (HDDA) were put into a mixing vessel in a weight ratio of70:10:10:6:4 (GlissopalSA:2021P:CN110:CN301:HDDA) at room temperature.As a radical initiator, 5 parts by weight of2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651, Ciba) was put intothe vessel with respect to 100 parts by weight of the main components,and 10 parts by weight of a photocationic initiator (Sa-apro, CPI-101A)was put into the vessel with respect to 100 parts by weight of the maincomponents. Also, as an inorganic filler, 3 parts by weight of fumedsilica (Aerosil, Evonik, R805, particle size: 10·20 nm, BET=150 m²/g)was put into the vessel with respect to 100 parts by weight of the maincomponents. Meanwhile, as a moisture absorbent, 10 parts by weight ofcalcium oxide (CaO, Aldrich) was further put into the vessel withrespect to 100 parts by weight of the main components.

A homogeneous composition solution was prepared by agitating the mixingvessel using a planetary mixing device (Kurabo Industries, KK-250s).

Example 3

As main components, an olefin-based resin, that is, an acidanhydride-modified polyisobutylene resin (Glissopal SA), curable resins,that is, a urethane acrylate (Sartomer, CN9013) and an epoxy acrylate(Sartomer, CN110), and reactive diluents, that is, a polybutadienedimethacrylate (Sartomer, CN301) and 1,6-hexanediol diacrylate (HDDA)were put into a mixing vessel in a weight ratio of 60:15:15:5:5(Glissopal SA:CN9013:CN110:CN301:HDDA) at room temperature. As a radicalinitiator, 5 parts by weight of 2,2-dimethoxy-1,2-diphenylethane-1-one(Irgacure 651, Ciba) was put into the vessel with respect to 100 partsby weight of the main components. Also, as an inorganic filler, 7 partsby weight of fumed silica (Aerosil, Evonik, R805, particle size: 10˜20nm, BET=150 m²/g) was put into the vessel with respect to 100 parts byweight of the main components. Meanwhile, as a moisture absorbent, 10parts by weight of calcium oxide (CaO, Aldrich) was further put into thevessel with respect to 100 parts by weight of the main components.

A homogeneous composition solution was prepared by agitating the mixingvessel using a planetary mixing device (Kurabo Industries, KK-250s).

Comparative Example 1

An adhesive composition was prepared by the same method as described inExample 1, except that a polyisobutylene resin (BASF, B14) was used asan olefin-based resin.

Comparative Example 2

An adhesive composition was prepared by the same method as described inExample 1, except that an olefin-based resin, that is, an acidanhydride-modified polyisobutylene resin (Glissopal SA), curable resins,that is, an alicyclic epoxy resin (Tohto Kasei, ST-3000) and an epoxyacrylate (Sartomer, CN110), and reactive diluents, that is, apolybutadiene dimethacrylate (Sartomer, CN301) and 1,6-hexanedioldiacrylate (HDDA) as main components were put into a mixing vessel in aweight ratio of 30:30:30:6:4 (GlissopalSA:ST-3000:CN110:CN301:HDDA), and3 parts by weight of an inorganic filler was put into the vessel withrespect to 100 parts by weight of the main components.

Comparative Example 3

An adhesive composition was prepared by the same method as described inExample 1, except that fumed silica (Aerosil, Evonik, RY 50, BET=30m²/g) as an inorganic filler was put into the vessel.

Comparative Example 4

An adhesive composition was prepared by the same method as described inExample 3, except that an olefin-based resin, that is, an acidanhydride-modified polyisobutylene resin (Glissopal SA), curable resins,that is, a urethane acrylate (Sartomer, CN9013) and an epoxy acrylate(Sartomer, CN110), and reactive diluents, that is, a polybutadienedimethacrylate (Sartomer, CN301) and 1,6-hexanediol diacrylate (HDDA) asmain components were put into a mixing vessel in a weight ratio of60:10:10:5:15 (GlissopalSA:CN9013:CN110:CN301:HDDA), and 3 parts byweight of an inorganic filler was put into the vessel with respect to100 parts by weight of the main components.

Hereinafter, physical properties in the examples and comparativeexamples were evaluated by the following methods.

1. Measurement of Viscosity and Thixotropic Index

Viscosities of the adhesive compositions prepared in the examples andcomparative examples were measured using a Brookfield viscometer,RVDV−II+Pro, as follows:

The measurement was conducted on the prepared adhesive composition at atemperature of 25° C. and a rotational speed of 0.5 rpm. Specifically,viscosity V_(0.5) was measured with respect to a torque at an RV-7spindle of the Brookfield viscometer. Also, viscosity V₅ was measuredwith respect to a torque at an RV-7 spindle of the Brookfield viscometerunder conditions of a temperature of 25° C. and a rotational speed of 5rpm.

From the viscosity measured as described above, a thixotropic index (TI)was calculated according to General Equation 1.T=V _(0.5) /V ₅  [General Equation 1]

2. Coating Property

A coating property was examined by applying the adhesive compositionsolution prepared in each of the examples and the comparative examplesto side surfaces of a 0.7T soda lime glass in a tetragonal shape havinga size of 150 mm×150 mm using a Musashi 200DS apparatus (needle number:#18, dispensing speed: 10/mm/sec). When there were no bubbling andblocking of a nozzle of the apparatus in coating, it was denoted as O,when bubbles were generated during coating or the composition was widelydiffused, thereby losing the original shape after coating, it wasdenoted as Δ, and when a large amount of bubbles during coating orcoating was ceased by blocking a nozzle, it was denoted as X.

3. Precipitation Stability

Precipitation stabilities of the adhesive compositions of the examplesand the comparative examples were evaluated as follows. The preparedadhesive composition was mixed and defoamed, injected into a syringe,and left at 25° C. for 3 days. Afterward, the coating was performed toevaluate if the inorganic filler was precipitated in a lower portion ofthe syringe. When an upper layer and a lower layer were coated with thesame amount of the inorganic filler and there was no blocking of anozzle, it was denoted as O, and when a nozzle was blocked duringcoating and the upper layer is more transparent than the lower layer, itwas denoted as X.

4. Thermal Resistance and Moisture Resistance

The adhesive composition solution prepared in each of the examples andthe comparative examples was applied to side surfaces of a 0.7T sodalime glass in a tetragonal shape having a size of 150 mm×150 mm using aMusashi 200DS apparatus. Afterward, the coated glass was laminated withthe same type of a glass, thereby preparing a sample. The adhesivecomposition was irradiated with light (a metal halide lamp) in the UV-Awavelength range at a dose of 3 J/cm², and heated in an oven at 100° C.for 3 hours (in Examples 2 and 3 and Comparative Example 4, irradiatedwith light at a dose of 5 J/cm²). Then, the sample was maintained in aconstant temperature and humidity chamber at 85° C. and relativehumidity of 85% for about 1000 hours.

In the measurement of thermal resistance, when there were no change in acoated region and on the side surfaces of the coated region, it wasdenoted as O, and when there was an empty space in the coated region, itwas denoted as X.

In the measurement of moisture resistance, when there was no lifting ina moisture-permeated part, it was denoted as O, and when themoisture-permeated part was lifted from the glass, it was denoted as X.

5. Compatibility

Compatibility was evaluated with respect to the adhesive compositions ofthe examples and the comparative examples. Phase separation was examinedafter the prepared adhesive composition was left in a vessel at 25° C.for 3 days. When phase separation did not occur in the composition, itwas denoted as O, when partial phase separation occurred, it was denotedas A, and when phase separation occurred into two layers, it was denotedas X.

TABLE 1 Thermal Viscosity Precip- resistance/ Thixotropic (0.5 rpm)Coating itation water Compati- index (TI) cPs property stabilityresistance bility Example 1 1.6 280,000 ◯ ◯ ◯/◯ ◯ Example 2 1.4 120,000◯ ◯ ◯/◯ ◯ Example 3 3.1 450,000 ◯ ◯ ◯/◯ ◯ Comparative 1.1 470,000 X ◯X/X X Example 1 Comparative 1.3 220,000 ◯ ◯ ◯/X Δ Example 2 Comparative1.1 170,000 X ◯ ◯/◯ ◯ Example 3 Comparative 1.3 89,000 Δ X X/◯ ◯ Example4

What is claimed is:
 1. An adhesive composition for encapsulating anorganic electronic element, comprising: an olefin-based resin having atleast one reactive functional group, a curable resin; a reactive diluentof Chemical Formula 1,

where R₁ is hydrogen or an alkyl group having 1 to 4 carbon atoms, n isan integer of 2 or higher, and X is a residue derived from a linear,branched or cyclic alkyl or alkenyl group having 3 to 30 carbon atoms,wherein a thixotropic index (T) according to General Equation 1 is inthe range of 1.35 to 5,T=V _(0.5) /V ₅  [General Equation 1] where V_(0.5) is a viscosity ofthe adhesive composition measured using a Brookfield viscometer with anRV-7 spindle at a temperature of 25° C. and a rotational speed of 0.5rpm, and V₅ is a viscosity of the adhesive composition measured using aBrookfield viscometer with an RV-7 spindle at a temperature of 25° C.and a rotational speed of 5 rpm, wherein the olefin-based resin includesan isobutylene-based homopolymer or copolymer, and wherein the adhesivecomposition comprises the olefin-based resin, the curable resin and thereactive diluent in an amount of 60 to 70 parts by weight, 20 to 30parts by weight and 10 parts by weight, respectively, and wherein theviscosity V_(0.5) is in the range of 100,000 to 1,000,000 cPs.
 2. Theadhesive composition of claim 1, further comprising: an inorganicfiller.
 3. The adhesive composition of claim 2, wherein the inorganicfiller has a BET specific surface area in the range of 35 to 500 m²/g.4. The adhesive composition of claim 2, wherein the inorganic filler iscomprised at 0.1 to 20 parts by weight with respect to 100 parts byweight of the olefin-based resin.
 5. The adhesive composition of claim1, wherein the olefin-based-resin has a weight average molecular weightof 100,000 or less.
 6. The adhesive composition of claim 1, wherein theat least one reactive functional group is an acid anhydride group, acarboxyl group, an epoxy group, an amino group, a hydroxyl group, anisocyanate group, an oxazoline group, an oxetane group, a cyanate group,a phenol group, a hydrazide group or an amide group.
 7. The adhesivecomposition of claim 1, wherein the curable resin comprises one or morecurable functional groups.
 8. The adhesive composition of claim 1,further comprising: an initiator or a curing agent.
 9. The adhesivecomposition of claim 1, further comprising: a moisture absorbent. 10.The adhesive composition of claim 9, wherein the moisture absorbent iscomprised at 5 to 100 parts by weight with respect to 100 parts byweight of the olefin-based resin.
 11. An organic electronic device,comprising: a substrate; an organic electronic element formed on thesubstrate; and a side encapsulation layer formed on a peripheral portionof the substrate to surround side surfaces of the organic electronicelement, and including the adhesive composition of claim
 1. 12. Theorganic electronic device of claim 11, further comprising: an entireencapsulation layer for covering the entire surface of the organicelectronic element, wherein the entire encapsulation layer is present inthe same plane as the side encapsulation layer.
 13. A method ofmanufacturing an organic electronic device, comprising: applying theadhesive composition of claim 1 to a peripheral portion of a substrateon which an organic electronic element is formed to surround sidesurfaces of the organic electronic element; irradiating the adhesivecomposition with light; and heating the adhesive composition.
 14. Theadhesive composition of claim 1, wherein the viscosity V_(0.5) is in therange of 100,000 to 460,000 cPs.